Magnetic coupling



' Jan. 1925B I E, T. wmumws;

MAGNETIC COUPLING:

Original Filed June 1. 1922 2 Sheets-Sheet 1 um/whom WW @McW/mmf Jan. 51926.

E. T. WILLIAMS MAGNETI C COUPLI NG 2 Sheets-Sheet 2 Original Filed June1, 1922 v avwcmtoc rater-sea Jan. race.

unirsn m EDWARD '1. WILLIAM$, 0F BROOKLYN, NEVIT 1 03K, ASSIG'NOR U? TULEAK/I 6. SMITH, 0E BEUUKLYN, NEW Y GG'QTFLING.

Application filed June '1, 1922, Serial To all whom it may concern 7 Beit known that I, EDWARD T. WiLLIAns, a citizen of the'United States ofAmerica, residing at Brooklyn, in the city of New York, county of Kings,and State of New York, have invented certain new and useful Improvementsin Magnetic Couplings, of which the following is a full, clear, andexact description.

In machines forhandling gases, as for example pumps, compressors,blowers, exhausters, and the like, in which a driving I or otherrotatingshaft extends out of the machine for connection with an external shaft,considerable difliculty is experienced in preventing leakage out of orinto the machine or casing, along or around the shaft. One method whichhas been proposed for meeting the conditions mentioned is to couple thetwo shafts magnetically. and cover the outer end of the inner shafthermetically by means of a cylindrical cup of nonmagnetic metal whichwill permit the magnetic flux of the driving element, rotating aroundthejcup, to pass to the driven element housed in the cup. This method,however attractive in theory, has not been successful in practiseheretofore; and it is accordingly the chief object of my presentinvention to provide a magnetic coupling of the type referred to, whichshall be free from the defects that' have made the prior devicesunsuccessful. To this and other ends the invention consists in the novelfeatures and combinations of elements hereinafter described.

()ne form of the invention illustrated in the accompanying drawing, inwhich Fig..l is alongitudinal section through the axis of the coupling.

Fig. 2 is a cross section on line 2-2 of B 1g. 1.

1g. 3 1s a longitudinal section illustratlug a'prior type ofconstructimi.

In the drawing, 10 represents the wall of a compresser or other machine,having a necltll, constituting a bearing for a shaft 12 and formed atits outer end with a radial flange l8. Rigidly mounted on the outer endof the shaft is a magnetic coupling member 14:, preferably laminated,and cruciform in shape, and around the member let is an outer rotatablemagnetic coupling member 15, mounted on a spider or dislrshaped carriol15 Which is fixed or. the

means.

No. 565,275. Renewed June 10, 1925.

jacent end of the driving shaft 17. lhe

ill)

negative as indicated by the plus and minus signs in 2. The windingterminals E20, 21, are connected to insulated slip rings 22, .253 onshatt l7. Energizing current is delivered to and received from the sliprings by means of brushes 2%, 25, suitably mount ed on a shell it;carried by the motor 17 From the foregoing it will be evident thatmagnetic flux between poles of opposite si n on the rotating outercoupling-member 15 passes "through the inner member and couples the twotogether, so that the inner member is revolved in harmony with theouter.

in order to prevent leakage into or out i of the casing 10 along theshaft 12, cover the inner coupling member 14- with ing cup or shield 2'?of non-magnetic me pr. (Lily phosphor bronze, having a rat flang heldfirmly and hermetically the 13 by means of a clamping ring 29. Thelatter has an axial flange 30 closely fitting and supporting theadjacent portion of the shield seal 27.

l -leretoi'ore the practise has been to make the shield or sealsubstantially cylindrical in form, as indicated at 31 in 3. This shapehas been the prime cause of laclr of cross in the prior constructions.in the place, the gap between the inner at; er coupling members must benarrow in order to insure reasonable efiiciency. 'lhis means that themetal shield must be made of thin sheet metal, to permit free rotationof the coupling members. But if the sure inside of the shield is at allhigh, 150 pounds or upwards, per square inch, Sheet metal of adequatethinness cannot withstand such pressure without slight deformation,evidenced by outward bulging of cylindrical walls. then, the couplingmembers are close enough together to make the apparatus etficient thebulging shield comes against the outer member and is speedily destroyed.Gin the other hand. if

the

ice

th'i

the

the metal of the shield is thick enoughto withstand the stresses exertedupon. it the gap between the coupling members must be correspondinglywide. end eificiency of the apparatus is seriously lessened.

In my constiuctiou htmevei' shield has a substantially sphericalcurvature throughout its unsupported area, preferably in the form of ehemisphere, as shown in F l, and the coupling members have theiradjacent surfaces inclined, preferably heving spherical curvature inclose conformity to the shield, as shown. In this form the shieldalready has the maximum volume for it superficial area, and consequentlythere is no tendency for it to depart fi om the spherical shape. 611 thecontrary the only tendency is to become a larger sphei'e. But thistendency is equal in all dii'ections and hence to become larger allports of the shell must stretch equally 'Wllldll means that the totalstrength of the. metal is fully utilized in resisting expansion. The netresult/is that there is no expansion at all, or if there is, it is sounifomnly distributed over the entire shell that the increase indiametei is 3 u p 11 w negligibly 33311111758. it one thereroi'e sole touse for the shell o metal of only tensile strength and still have itthis enough (soy around 1115 of an inch) to give'sotis- :tactoi'yelficiency. v

l do not mean to soy thatthe entire unported area of the shell must bespheri @u the contz'oi'y the portion to the supporting Ell -31 can othesvise sloped; for example cylinos'ical shown t in such case the. nonvspherical part of the shell should be short its axial length preferablynot exceediz g say about one or one fourth of the diameter, and thecoupling members should extend Well over upon the spherical portion. Noris it necessary to make the shell of metal having high tensile strength.Phosiohoi bronzois satisfactory in most not ll cases, and in genci'slneed not be more 915 of en inch thi l Withs and a some as high aslellounds square 7 Without el igatiox diameteix @ther metals 113? be aresubstantially non-i .fL lstively W l c through o well of the later,

tei'iding through a wall of the latter, an outer 'couolin elements andillustrated and described but can be cmloodied in other forms Withoutdeparture from its spirit. 1

l clsim- 1. The combination of a machine havin a closed casing and aninner shaft extendlng an outer shaft, outer and inner magnetic couplingelements carried by said shafts to drive one from the other, and asealing shell of which substentially all the unsupported area is ofsubstantially spherical, curvature enclosing the inner coupling elementand heremetically scaled to the casing.

2. The combination of a machine havin a closed casing and an inner shaftextending'through a Wall of the casing, an outer she-ft, outer and innermagnetic coupling elements carried by said shafts to drive one from theother, and a sealing shell substantially hemispherical in form enclosingthe inner coupling element. and hermetically scaled to the casing.

3. Thecombinationof a machine having alclosed casing and an inner shaftexsha'ft, outer and inner magnetic coupling elements carried by saidshafts to drive one from the other and a sealing shell of whichsubstantially the entire unsupported area is substantially sphericalcurvature cnclo'siug the inner coupling element and he1'met icallysealed to the casing; the adjacent feces of the coupling elements beingshaped in substantial conformity to the curvature c; theshell. I

The'combiuation' 'of a machine having a closed casing and a shaftextending through a Wall thereof, a magnetic coupling element carried bythe outer end of the shaft and'having its outer surface substantiallyspherical in curvature, an outer shaft aligned With the inner shaft, amagnetio; coupling element carried by the outer shaft, embracing thefirst mentioned couplin ele meet and having its inner surfacesubstantially spherical in curvature, and a substantially hemisphericalscaling cup bet-ween the hermetically sealed to the seid casing.

'"fl stimony whereof I hereto

